Rect类的使用结果

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import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Rect;import android.util.Log;import android.view.View;public class MyRect extends View {    Paint paint = new Paint();    Rect r1 ;    Rect r2 ;    Rect r3 ;    public MyRect(Context context) {        super(context);        init();    }    private void init() {        r1 = new Rect(10, 10, 100, 100);        r2 = new Rect(110, 110, 180, 180);        //判断是否相等，重写了equals        Log.i("equals", r1.equals(r2) + "");//equals﹕ false        //重写了toString        Log.i("toString", r1.toString());//toString﹕ Rect(10, 10,  100, 100)        Log.i("toShortString", r1.toShortString());//toShortString﹕ [10,10][100,100]        Log.i("flattenToString", r1.flattenToString());//flattenToString﹕ 10 10 100 100        r3 = Rect.unflattenFromString("180 180 280 280");        Log.i("isEmpty", r1.isEmpty() + "");//isEmpty﹕ false        Log.i("r1-width", r1.width() + "");//r1-width﹕ 90        Log.i("r1-height", r1.height() + "");//r1-height﹕ 90        // 中心X坐标        Log.i("r1_centerX", r1.centerX() + "");//r1_centerX﹕ 55        //中心Y坐标        Log.i("r1_centerY", r1.centerY() + "");///r1_centerY﹕ 55        //精确的中心X坐标        Log.i("r1_exactCenterX", r1.exactCenterX() + "");//r1_exactCenterX﹕ 55.0        //精确的中心Y坐标        Log.i("r1_exacctCenterY", r1.exactCenterY() + "");//r1_exactCenterY﹕ 55.0        //重置为空        r2.setEmpty();        //设置坐标        r2.set(40, 40, 100, 100);        printCoordinates(r2, "a");        //left﹕ 40        //top﹕ 40        //right﹕ 100        //bottom﹕ 100        //使用已有的Rect进行设置        r2.set(r1);        printCoordinates(r2, "b");        //left﹕ 10        //top﹕ 10        //right﹕ 100        //bottom﹕ 100        //偏移        r1.offset(20, 20);        printCoordinates(r1, "c");        //left﹕ 30        //top﹕ 30        //right﹕ 120        //bottom﹕ 120        //偏移到        r1.offsetTo(40, 40);        printCoordinates(r1, "d");        //left：40        //top﹕ 40        //right﹕ 130        //bottom﹕ 130        r1.inset(20, 30);        printCoordinates(r1, "e");        //left﹕ 60        //top﹕ 70        //right﹕ 110        //bottom﹕ 100        //判断包含性        Log.e("contains1", r1.contains(50, 50) + "");// contains1﹕ false        Log.e("contains2", r2.contains(20, 20, 80, 80) + "");//contains2﹕true        Log.e("contains3", r3.contains(r2) + "");//contains3﹕ false        //判断相交        Log.e("intersect1", r1.intersect(50, 50, 60, 80) + "");//intersect1﹕false        Log.e("intersect2", r1.intersect(r2) + "");//intersect2﹕ true        Log.e("intersects3", r1.intersects(50, 50, 60, 80) + "");//intersects3﹕ false        Log.e("intersects4", Rect.intersects(r2, r3) + "");//intersects4﹕ false        //取相交部分        Log.e("setIntersect", r1.setIntersect(r2, r3) + "");//setIntersect﹕ false        printCoordinates(r1, "r1a");        //left﹕ 60r1a        //top﹕ 70r1a        //right﹕ 100r1a        //bottom﹕ 100r1a        //取并        r1.union(r2);        printCoordinates(r1, "r1b");        //left﹕ 10r1b        //top﹕ 10r1b        //right﹕ 100r1b        //bottom﹕ 100r1b        r1.union(8, 7);        printCoordinates(r1, "r1c");        //left﹕ 8r1c        //top﹕ 7r1c        //right﹕ 100r1c        //bottom﹕ 100r1c        r1.union(40, 20, 120, 130);        printCoordinates(r1, "r1d");        //left﹕ 8r1d        //top﹕ 7r1d        //right﹕ 120r1d        //bottom﹕ 130r1d        //交换        r1.sort();        printCoordinates(r1, "r1e");        //left﹕ 8r1e        //top﹕ 7r1e        //right﹕ 120r1e        //bottom﹕ 130r1e    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawRect(r1, paint);        canvas.drawRect(r2, paint);        canvas.drawRect(r3, paint);    }    /**打印坐标*/    private void printCoordinates(Rect rect, String str) {        Log.i("left", rect.left + str);        Log.i("top", rect.top + str);        Log.i("right", rect.right + str);        Log.i("bottom", rect.bottom + str);    }}

Rect rect=new Rect(100,50,300,500);

那么右下角(300,500)其实是不在这个矩形里面的，但是左上角(100,50)在，也就是说，这个矩形实际表示的区域是：(100,50,299,499)。另外，Rect计算出的Height和Width倒是对的。所以，在此告诫各位程序员，在涉及Rect运算的时候，尽量不要使用它的右下角左边，即right和bottom。因为他们是错的。

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